import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Text {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        // 注意 hasNext 和 hasNextLine 的区别
        int n = in.nextInt();
        int[] arr = new int[n];
        for (int i = 0; i < n; i++) {
            arr[i] = in.nextInt();
        }
        int minBuy = arr[0];
        int maxProfit = 0;
        for (int i = 0; i < arr.length; i++) {
            if(arr[i] < minBuy){
                minBuy = arr[i];
            }else {
                int profit = arr[i] - minBuy;
                if(profit > maxProfit){
                    maxProfit = profit;
                }
            }
        }
        System.out.println(maxProfit);
    }
}